George wyckoff cummins and james henry coleman



(No Model.)

G. W; OUMMINS & J. H. COLEMAN. PROCESS OF PREVENTING THE OXIDATION OF METALS WEILE IN A HEATED CONDITION.

No. 409,276. Patented Aug. 20, L889.

ii 1% 3 I 6 'm-E UNITE STATES- PATENT OEFIcE.

eEoBeE W'YCKOFE CUMMINS AND JAMES HENRY COLEMAN, on NEW HAVEN, CONNECTICUT.

PROCESS OF PREVENTING THE OXIDATION OF METALS WHILE IN A HEATED CONDITION.

' SPECIFICATION forming part of Letterslatent No.409,276, anti August 20, 1889.-

Application filed July It, 1888- Berial No. 279,990- i (No inodel.)

To all whom) it may concern: 1

Be it known that we, GEQRGE-WYOKOFF CUMMINs and JAMES HENRY COLEMAN, of NewTHavemin the county of New Haven and State of Connecticut, have invented a new and useful Process of Preventing the Oxidation of Iron or Steel while in a Heated Condition, notably while undergoing such heating as is usual in annealing operations, which invention is fully set forth and illustrated in the following specification and accompanying drawings.

The object-of this invention is sufliciently disclosed by the above-made statement of its of said generator or furnace.

purpose, and the invention will therefore now be described in detail, and then particularly set forth in the claim. a

An apparatus or plant suitable for carrying'out this invention is illustrated in the accompanying drawings, in which,-

Figure 1 shows in sectional side elevation a view of the entire plant. Fig. 2 shows in front elevation a generator or furnace, forming part of Fig.1. Fig. 3 is a rear elevation 1 In said figures the several parts are indifollows":

. 1 indicates a gas-generator; 2, a cooler; 3, a

desiccator, -and 4 an annealing pot or chamher. The cooler and annealing-pot may be cylindrical in exterior shape, if preferred, and therdesiccator preferably square or rectangular. The severalparts above named maybe described as follows: t

The furnace or generator l c'onsists of castiron retorts A, two or more in number, protected by fire-brick B, set within ordinary brickwork A, such as is used for the setting of coal-gas retorts. The retort'sA are heated by a furnace or furnaces C, provided with grates c and appropriate fines, as in furnaces for the generation of coal-gas. The retorts A are each closed by doors d at each end and provided at one'end with an inlet-pipe D and at the other end with an outlet-pipe E, each of which outlets delivers into one common outlet-pipe H. The pipe F connects the two pipes *E, and from the pipe F the pipe G leads to the escape-flue or chimney I. Valves K,

L, and M govern the flow of the gas asdesire'd, the special OlfiCB of which valves will be hereinafter, more particularly described.

The cooler 2 may be made with a worm w,

as shownin the drawings, for the gas to pass through, like any common still or condenser, any moisture condensed within said worm from the gas being drawn off through the cock N, the cooling-water entering at a and leaving at b, or vice versa. A gas-holder of any common and well-known form-such as is used for storing common illuminating-gas may be, if desired, located between the cooler 2 and the desiccator 3. The size of this holder will be determined by thequantity of gas desired tobe stored. The smaller its size, however, the less costlythe construction and materials of the holder will be.

The desiccator 3 consists of a closed box or chamber containing trays or shelves t, on

which is placed fused calcium chloride. Said trays are so arranged'that the gas entering at 0 must pass over a considerable surface of said chloride before emerging at P. Instead of calcium chloride, pumice-stone moistened with concentrated sulphuric acid may be substituted. This substituted desiccating material has the advantage that the pumice-stone does not need removal or renewal, for so long as supplied with the acid it is a rapid and thorough desiccator. The acid is readily renewed without opening the desiccator by permitting it-to trickle or fall in drops on the pumice-stone, through suitable pipes or orifices in the walls of the desiccator, over the pumice-stone.

Of course it is understood that iron or steel, when heated to redness, readily absorbs oxygen at its surface from atmospheric air or any other source from which it can obtain oxygen, the surface of the metal thereby becoming rough and covered with scales of we ide. The endeavor therefore,-under such circumstances, in the treatment of metals is to exclude, as far as -.possible,.from the presence of the hot inetalall sources or media whence it can absorb oxygen. Even in annealing heretofore, while the anncaling-vessels'were have bee'nthus expelled from the charcoal or;

This invention excludes the atmosphere and substitutes therefor an artificial atmos phere,'which entirely surrounds the metal from before itis heated until it has. been cooled, or through the I-annealing process of both heating and again cooling, The artificial atmosphere or gas usedby us for this purpose maylbe said to be a mixture. t n'itrogen, carbonic oxide, and. carbonic acid water. Without confining ourselves to these proportions, itniay be statedthat the gas may consist of aboutsixty-eightpercent of nitrogen, about twenty 'sevento' thirty-three per cent. of carbonic oxide, and from a trace to L f about; four per cent. of carbonic acid.

. The gas, as prepared in the processbelow described, is non-inflammable. and non-explosive', andgis. entirely inert j as to any action upon iron or steel at any temperature, but a perfect preventive of oxidation, while the met'alis excluded from the airby its presence.

The method .ofmanufacturing the gas necessary for conducting the operation of; treat;-

ing the metalitherewith, and the processof so treatingthe inetal, will now be described. 2 When theretort A'has been heatedrto'i'ncandescence by the furnace O, the former is filled with charcoal or coke, which, as scion as it becomes sufliciently heated, evolves a gas somewhat of thenature of ordinary coalegas, but as isuchggas had nearly all been pre- -viously removed from the charcoal or coke in the production-of the same'the evolution of such gas is of short duration. This preliminary gasproduct'is inflammable and not at all suited to the purposes of the invention.

On the-contrary, it is injurious to'the metal tobe treated. Said gas'is therefore ermitted to, escape; through the pipes'G an F or F, provided with the valves K -K' and L L. .When the evolution of said gas ceases, a cur- .rent or blast of air is introduced at- J through y of gases, though possibly retaining a trace of the pipe or pipes Danvalve or valves M from any suitable blower (not shown) and 1 forced through the mass of incandescent'charcoal or coke. -lThis blast is permitted for-a short time toescape into the atmosphere through the pipe G and flue, or chimney I.

'When, all waiter'y and hydrocarbon vapors 'coke, the gas-thenevolved by the'blast of 'air may be regarded consisting, essentially, of nitrogen, 'earbonicoxide, and carbonic acid,

the first andla'st gases being considerably in excess of the carbonic oxide. This mixture watery vapor, is ready and fit to be passed from the-generator 1,, to the cooler 2 and .thence through the desiccator 3. In: its passage through this latter vessel the last trace qt ,watery'va'po'r is removed from the gas, and it is then in suitable condition tobe passed 5 described until needed for-use in the annealinto the annealing chamber or pot, or it may be' first stored in a gas-holder such as above ing process.

(N C0 C0 entirely freed from the vapor'of @In the practical conduct of the operation only one of the retorts A need be used at the same time for the production of the blastgas. Immediately upon ceasing to use the.

gasfroinone retort and commencing touse it from the other the charge of charcoal or coke is renewed in the first retort and allowed to become heated until the charge in the second retort is about half exhausted by the air 1blast.

duction and supply of suitable blast-gas is' secured. V I The annealing chambers,boxe s, or pots are By-this time the charge in the first 7 retort has reached the condition of freedom,

kept filled with the gas under a steady pressure while the same are both being heated and 'yvhile beingpermitted to cool, the gas-entering through pipe S and valve R and leaving".

moval therefromof the articles subjected to such gas in the annealing process no change whatever will be observed to have been produced in bright iron due to its exposure to .through pipe T and valve V. Upon the rep such gas. The'air is forced-through the,re-'

torts by displacement rather than exhausted therefrom, because any. leakage thatmay 00 cur must be outward and not inward; for it the leakage were inward the admixture ,of 7

external air. that would in such manner take place would change essentially and deteriorate the properties. of the gas.

.Even were the blast-gas absolutely free from watery vapor when leaving the retort-s, the interposition of the cooler is necessary; for if the blast-gas were permitted while hot to enter the cold annealing-vessels and while the metal therein was surrounded with cold air the admixture of the hot gas with 'such cold air would create a medium surrounding the metal that would oxidize the metal, As it is necessary to start the operation only when the annealing,- .vessel'is cold and to keep up the blast of gasuntildthe annealing is complete,

by which time the annealing-vessel has cooled down considerably, though not necessarily enough for a fresh start, the further cooling of such artess'elmay' be hastened somewhat,

if 'desired,"by'passing the cold gas through it before starting a new annealing operation. Oxidizable metals treated by this process are specially well suited to'be plated with non- 'oxidizablemetals (or galvanized) by reason of the bright, smooth, and clean surface they possess, entirely free ,from the roughness and foreign element of oxidation.

We do not confineourselves to the apparatus or plant herein described for generating and applying the gases named, as it is evident that the apparatus may be greatly varied withbut changing the process or the-product Having thus fully described our said pro cess as'cf our invention, we claim- Thehereinbefoi'e-described process of treating metals to prevent their oxidation'while in a, heated state, consisting in subjecting such metals to an atmosphere composed of nitro-= gen and carbonic oxide, with or withont carbonlc acid, the carbonic oxide being in suflicient excess to overcome any tendency of the carbonic acid, if present,t0 oxidize the metal, [C substantially as set forth.

I G. WYOKOFF OUMMINS.

J. HENRY'fiOLEMAN.

NVitnesses:

FRANCIS P. REILLY,

ALFRED S. BROWN. 

